program naming convention

[sixstring]

Hi all, im an absolute beginner (only installed ubuntu yesterday) and am trying to learn programming in c++ and python in a linux environment for a project I have to do in the future. I have made my first program, a simple hello world, to get to grips with using the g++ compiler and linux terminal but am having troubles running it when I name it in certain ways.

If its named hello, i can type it into terminal, hit enter and get the correct output, that is,

davidbush@davidbush-desktop:~$ hello
Hello, world!

If I name it Hello on the other hand I get
bash: Hello: command not found

but if i use ./Hello I get,

davidbush@davidbush-desktop:~$ ./Hello
Hello World!davidbush@davidbush-desktop:~$

where I get the output but seems to be joined onto the prompt (if its called prompt in linux terminology).

I understand I could just name all my programs in lower case and things should work fine but am just curious as to why this happens. Any insight would be much appreciated. Thanks

[Repentinus]

hello - system command.
Hello - command doesn't exist
./Hello - run program "Hello" in current dir.

If you want that text from your "Hello, world" program isn't joined with "davidbush@davidbush-desktop:~$" then output newline after "Hello, world!".